The invention generally relates to a method and apparatus for cleaning artificial dialyzers which are employed as artificial kidneys in dialysis treatments.
At present, the three general types of dialyzers which are known and available are the hollow fiber, parallel plate, and coil type dialyzers.
The hollow fiber dialyzer consists of multiple mutually parallel tubular membranes in close proximity to one another. The core of the fibers comprise the blood side of the dialyzer and the channels formed by their exteriors from the dialysate side. Parallel plate dialyzers consist of a series of parallel planar membranes. The membranes divide the dialyzer into alternating blood and dialysate sides. The coil type dialyzer consists of at least two membranes rolled into a spiral configuration. This configuration produces concentric circular pathways which form alternating blood and dialysate compartments.
After a dialysis treatment has been completed various membranes of the dialyzer are filled with a mixture of saline and blood. Historically, dialyzers in general were not thought to be reusable after the dialysis treatment. However, there have been attempts to design manual and/or semi automatic systems which would wash and disinfect/sterilize the dialyzer in preparation for a subsequent dialysis treatment.
One such attempt is disclosed in U.S. Pat. No. 3,753,493 issued to Mellor. This patent discloses a dialyzer apparatus which has a clean water inlet and an inlet for introducing cleaning and/or sterilizing liquids. Such liquids are then delivered into the water stream and circulated in parallel through the dialysate and blood sides of the dialyzer in one direction. A timer is used to control the sequential delivery of the water flow and cleaning liquid through the dialyzer. This controller is simply a clock which sequences the steps of the cleaning process.
U.S. Pat. No. 3,871 issued to Shaldon discloses another system for cleaning a dialyzer. In Shaldon, a dialysis fluid, fresh water and sterilizing fluid are respectively introduced into the dialyzer for respectively washing, rinsing and sterilizing it.
Both the Mellor and Shaldon systems fail to provide the necessary identification, monitoring, control and verstaility necessary to produce a truly safe, efficient and practical dialyzer cleaning system. For example, neither system provides tests during the cleaning process to determine whether the dialyzer meets certain reusability criteria.
The systems lack the capacity to automatically machine sequence a repetition of cleaning steps or to automatically augment the cleaning steps depending upon whether the dialyzer passes or fails these reusability criteria. The systems do not provide for differing cleaning processes for the different types of dialyzers, nor do they provide for the simultaneous application of differing cleaning steps to the blood and dialysate sides of a particular dialyzer. In addition, the systems also lack the capacity to automatically inhibit the cleaning sequences if the dialyzers are in a non-reusable condition. Finally, although it is known that a dialyzer should be reused only with the same patient, the systems lack safety checks necessary to insure that the proper patient will receive the proper dialyzer, and that, if any failures in the system occur, they will be fully traceable and will not be used to inhibit any further cleaning.
As a consequence of the ineffectiveness of prior systems, dialyzers are routinely discarded after each dialysis treatment, thus, making the cost of such treatments even more expensive.
There is, therefore, a distinct need for a fully automated dialyzer cleaning process and apparatus which will provide safe, efficient, versatile and controlled cleaning of dialyzers.